1. Field of the Invention
The embodiments of present invention are directed to an electronic device and an operation method thereof. More particularly, the embodiments of present invention are directed to a voltage generator, an oscillation device and an operation method thereof.
2. Description of Related Art
A voltage-controlled oscillator (VCO) circuit is an electronic oscillator circuit serving to control an oscillation frequency based on an input voltage. The oscillation frequency of the VCO circuit varies with different levels of the input voltage. Nevertheless, in a conventional VCO circuit, when an operation power is failed, related parameters (e.g., the oscillation frequency and so on) that are already calibrated will also be lost, and the oscillation frequency of the VCO circuit has to be reset and refine-tuned by a user (or a system) after the conventional VCO circuit is re-started (re-powered on).